The present invention relates to a line segment of a fuel line in an aircraft for connecting at least three lines, an aircraft with a line for connecting refueling cells, the use of a line segment in an aircraft, and a method for producing a line segment.
Fuel lines are used in aircraft for connecting fuel tanks with appliances, as well as, for example, also for connecting several fuel tanks with each other. EP 1217286 A2 discloses a line that has been installed double walled. Additional fuel tanks are used, for example, in refueling aircraft by means of which, for example, other aircraft can be refueled in midair. It has become evident that the adapter lines and connector lines are becoming increasingly complex and must meet higher safety requirements. In addition to the simple line segments, this also applies to those line segments by means of which several lines are connected with each other, for example, for connecting a tank unit to a supply line.
For this reason there is a need to provide fuel channeling in an aircraft that has, for example, better properties with respect to damage or leakage.
This is achieved by a line segment of a fuel line in an aircraft for connecting at least three lines, by an aircraft, by the use of a line segment in an aircraft, as well as by a method for producing a line segment of a fuel line according to one of the independent claims.
According to an exemplary embodiment of the invention, a line segment of a fuel line in an aircraft for connecting at least three lines has a wall structure which forms a continuous cavity. The wall structure has at least three adapter openings for connecting the continuous cavity with respectively one line. The wall structure has a double walled design between the adapter openings in such a way that an intermediate cavity is formed, that encases the continuous cavity.
According to a further aspect of the invention, the adapter openings point in various directions.
According to a further aspect of the invention, the wall structure is provided with an inner wall and an outer wall.
According to a further aspect of the invention, the continuous cavity has a round cross-section at the adapter openings, whereby the cavity is designed in such a way that the adapter openings are connected with each other by chamfered inner wall sections.
For example, the chamfered walls are configured for a fuel flow of at least approximately 1,200 kg/min, in particular at least 1,800 kg/min. Preferably, the line segment according to the invention is configured for such a flow rate in both directions in order to allow a quick filling of the tanks and also a quick supply of fuel to other systems, for example, when refueling other aircraft in midair.
Thereby, the high internal pressures must be taken into consideration at different ambient pressures, i.e., the walls must be designed correspondingly robust, but must simultaneously be as light as possible.
According to a further aspect of the invention, the inner wall forms the continuous cavity, i.e., the inner wall surrounds the continuous cavity except for those sections that have the openings.
According to a further aspect of the invention, the outer wall is located at a distance to the inner wall and encloses the inner wall completely, i.e., except for those sections that have the openings.
According to a further aspect of the invention, the inner and the outer wall are at a uniform distance from each other.
According to a further aspect of the invention, the inner and the outer wall are located concentrically to each other, i.e., in those sections that have a round cross-section.
According to a further aspect of the invention, the inner wall is produced integrally.
According to a further exemplary embodiment of the invention, the wall structure has an inner wall and an outer wall, whereby at least the outer wall consists of two half-shells.
According to a further aspect of the invention, the inner wall and the outer wall are respectively provided as cast work piece.
According to a further aspect of the invention, the outer and/or inner wall is a press-forged work piece or a deep-drawn work piece.
According to a further aspect of the invention, at the adapter openings, one adapter flange is formed respectively, whereby the inner wall and the outer wall are connected with each other via the adapter flanges.
According to one exemplary embodiment of the invention, one adapter flange is respectively formed at the adapter openings, whereby the inner wall and the outer wall are connected with each other via the adapter flange. The adapter flanges have two connector bars that are formed on the diametrically opposed side of the connection faces and which stick out in the direction of the walls that are to be connected. The inner wall and the outer wall are connected with the facing sides of the connector bars.
According to a further aspect of the invention, the connector bars extend concentric, whereby an inner and an outer bar are formed. The inner wall is connected with the inner bar and the outer wall with the outer bar.
According to an exemplary embodiment of the invention, the line segment is a T-piece that has a T-bar and a T-flange, whereby a first connection is provided at the end of the T-bar, and whereby a second and third connection is provided at the two ends of the T flange.
According to a further aspect of the invention, the outer wall consists of two half-shells, whereby the two half-shells extend in a mirror image to a plane in the T-piece, which extends in the axis of the T-bar, and which is located transverse to the direction of the T-flange.
According to a further aspect of the invention, the two half-shells are mirror images to a plane that extends in the axis of the T-bar and in the axis of the T-flange.
According to a further aspect of the invention, the two half-shells consist of a sectional plane that extends through the axis of the T-flange and in a plane that is perpendicular to the T-bar.
According to a further aspect of the invention, the inner wall has a first reinforcement structure at the side facing away from the continuous cavity.
According to a further aspect of the invention, the outer wall has a second reinforcement structure.
According to a further aspect of the invention, the outer wall has the second reinforcement structure at the side facing away from the intermediate cavity.
According to a further aspect of the invention, the reinforcement structure on the T-piece is provided at the lateral sections of the T-bar.
According to a further aspect of the invention, the reinforcement structure encloses the inner wall of both lateral sections of the T-bar, starting from the T-flange.
According to a further aspect of the invention, a rib structure is provided between the inner wall and the outer wall, which has at least one rib.
According to one exemplary embodiment of the invention, a rib structure is provided between the inner wall and the outer wall, which has at least one rib, whereby the at least one rib is designed integral with the inner wall, and whereby the two half-shells of the outer wall are fastened at the rib.
According to a further aspect of the invention, the T-piece has a rib at the lateral sections of the T-flange.
According to a further aspect of the invention, a rib is provided on the T-piece at the T-flange at the side that is diametrically opposed to the T-bar, i.e., at that side which has no branching, i.e., at that side that is opposite to the branching of the T-bar.
According to a further aspect of the invention, the rib on the T-piece is provided at the lateral branches of the T-bar, whereby the rib starting at the first opening encloses the T-flange.
According to a further aspect of the invention, several ribs are provided in combination according to the preceding examples.
According to a further aspect of the invention, at least one rib is provided which is located inclined relative to the T-bar, T-flange and their virtual axes.
According to a further aspect of the invention, the rib—with its inner wall—forms an H-shaped profile in cross-section with two H-flanges that are connected by an H-bar, whereby the inner wall forms one of the H-flanges.
According to a further aspect of the invention, the outer wall is fastened at the other one of the two H-flanges.
According to a further aspect of the invention, the outer wall is fastened respectively at the facing sides of the other H-flange.
According to a further aspect of the invention, the walls consist of metal and are welded at the facing sides.
According to a further aspect of the invention, the individual components, for example, the walls and/or the adapter flanges are made of one work material because of expansion. For example, the component parts for the line segment are assembled by laser sintering, for example, by rapid prototyping, rapid tooling, rapid manufacturing, etc.
According to a further aspect, the parts are produced by laser welding.
According to a further aspect of the invention, the individual components, for example, the walls and/or the adapter flanges are assembled using a laser by adding titanium wire (i.e., rapid prototyping).
According to a further aspect of the invention, the rib structure divides the intermediate cavity into at least two intermediate spatial sections, whereby the at least one rib has at least one rib opening, through which two adjacent intermediate spatial sections are connected with each other.
According to a further aspect of the invention, at least one of the adapter flanges has at least one flange opening that forms an opening of the intermediate cavity on the facing side.
According to a further aspect of the invention, in a T-piece, the adapter flanges that are located diametrically opposed, i.e., the adapter flanges provided at the ends of the T-flange, respectively have at least one flange opening. For example, several flange openings are provided.
According to a further aspect of the invention, the intermediate spatial sections of the intermediate cavity are connected with each other via a number of openings in the rib structure in this way and are accessible via the flange openings respectively provided at the adapter flanges, so that fuel leaking into the intermediate space can be captured at a suitable location in the event of leakage. For example, a leakage drain (leak monitor) can be provided in a lower section of a fuel line to control and detect leakage amounts.
According to a further aspect of the invention, in a T-piece at the lateral sections of the T-bar, mounting positions are provided for connecting to structures that are exposed to loads.
The invention also relates to an aircraft with a fuselage design, an aerodynamic lift system, a propelling system and a fuel storage system, whereby the fuel storage system has at least two refueling cells that are connected with a fuel line. The line has a line segment according to one of the previously cited exemplary embodiments and aspects of the invention.
The propulsion system can, for example, include one or more jet engines or propeller drive units. The aerodynamic lift system includes, for example, two wings sticking out laterally from the fuselage design. The term aerodynamic lift system includes, for example, also pitch elevators in the section of the main deck, as well as in the posterior section of the aircraft, and one or more fins. According to one aspect of the invention, in addition to the fuel tank systems required for the actual flight operation, additional refueling cells are also present with which the range of the aircraft can be increased, or by means of which refueling of other aircraft is possible in midair.
For example, in a fuselage design that is, for example, also suitable for transport purposes, several refueling cells can be located in the cargo hold, for example, also in the anterior and in the posterior section, whereby a fuel line system can be present through which the two refueling cells can be connected.
The invention also relates to the use of a line segment according to one of the previously cited exemplary embodiments, as well as aspects in an aircraft.
The invention further also relates to a method for the production of a line segment of a fuel line in an aircraft for connecting at least three lines with at least three adapters, whereby the method includes the following steps:
a) Locating a first half-shell of an outer wall at an integral inner wall in such a way that an intermediate cavity is formed between the inner and the outer wall. The inner wall forms a wall structure that encloses a continuous cavity. The wall structure has at least three adapter openings for connecting the continuous cavity with respectively one line;
b) locating a second half-shell of an outer wall at the inner wall in such a way that an intermediate cavity is formed between the inner and the outer wall, whereby the intermediate cavity encases the continuous cavity.
c) connecting the first half-shell of the outer wall with the second half-shell of the outer wall; and
d) connecting the outer wall with the adapter flanges, of which one is provided at each adapter opening, whereby the connection is done in such a way, that the outer wall is connected with the inner wall via the adapter flange.
According to one exemplary embodiment, prior to step d), an adapter flange is located at each adapter opening and in step d), the adapter flanges are also connected with the inner wall.
According to a further aspect of the invention, the inner wall is made available integral with the adapter flanges.
According to a further aspect of the invention, the connections are executed at least in part as butt joints.
According to a further aspect of the invention, the sections for the butt joints are designed more robust and prior to being placed, the sections are adapted to each other by machining.
According to a further aspect of the invention, at the positions that are to be connected, at least some positioning devices are provided.
According to a further aspect or the invention, the butt joints are provided as welded connections and the positioning devices are provided as additional edges of welded material, whereby the additional material is used in the connection steps for welding.
According to a further aspect of the invention, a reinforcement rib is provided at one inner wall and in step c), the first and the second half-shell are connected with each other via the reinforcement rib.
According to a further exemplary embodiment of the invention, the first and the second half-shell are produced with an integral wall. The integral wall is separated into two half-shells by using a cutting process along a joint. At the inner wall, a reinforcement rib is provided, whereby the reinforcement rib and the joint are adapted to each other with respect to their dimensions. The connection takes place in step c) in the section of the joint, whereby the first and the second half-shell are connected with each other via the reinforcement rib.
According to a further aspect of the invention, the adapter flanges are machine-finished on their connection face according to step d).
It should be noted that the characteristics of the exemplary embodiments and aspects of a line segment, as well as the aircraft, also apply to the embodiment forms of the method, as well as the use of the fuel line system and vice versa.